When the database is first created, there are some basic parameters that are most necessary.
We can see these parameters with the following query,
SQL> select name from v$parameter where isbasic=’TRUE’ order by 1;
There are 342 parameters in the database. But 30 of them are absolutely necessary. Now let’s examine them closely.
cluster_database
Parameter Type: Boolean(True/False)
Default Value: False
This parameter is used if Oracle RAC is used. This value is false in single instance installations.
compatible
Parameter Type: String
Default Value: 11.2.0
Available Values: 10.0.0 to default version
Determines the compatibility version of our database.
Example: compatible=’11.2.0.0.0′
control_files
Parameter Type: String
Available Values: File name 1 to 8
These are the parameters that specify the name of our control files and the directories in which they are located, such as the brain of the database. The database must have at least one control file to run.
Example: control_files=’+DATA/TESTDB/CONTROLFILE/current.262.1018656187′
db_block_size
Parameter Type: Integer
Default Value: 8192
Available Values: 2048 to 32768
The size of the database blocks, expressed in bytes. The default value is 8 kilobytes, which is 8192 bytes.
db_create_file_dest
Parameter Type: String
Default Value: No default value!
It is used to specify the default directory of data files and online redo log files used by the database.
Example: db_create_file_dest=’+DATA’
db_create_online_log_dest_n
Parameter Type: String
Default Value: No default value
The values that the number n can take at the end of the parameter are 1,2,3,4 or 5.
Used to specify the default directory of the control and online redo log files used by the database. With db_create_online_log_dest_1 and db_create_online_log_dest_2 parameters, we can keep copies of redo log files on different disks.
db_domain
Parameter Type: String
Default Value: No default value
If you are using a domain, this parameter can be used to reflect the full name of the database so that your domain name cannot exceed 128 characters.
Example: DB_DOMAIN=domain_name
db_name
Parameter Type: String
Default Value: No default value
The name we give to the database when creating a database.
db_recovery_file_dest
Parameter Type: String
Default Value: No default value
Fast Recovery Area (FRA) is the parameter used to specify the default directory. This field contains backups, archive log files, flashback log files, online redo log files and control files made with RMAN.
Example: db_recovery_file_dest=+DATA
db_recovery_file_dest_size
Parameter Type: Big Integer
Default Value: No default value
The size information used by the FRA field is determined by this parameter in kilobytes, megabytes or gigabytes. If this space is insufficient, Oracle performs an automatic deletion starting from the oldest files.
db_unique_name
Parameter Type: String
Default Value: Database Name
If we want to create an exact copy of a database and the databases will be of the same name, we need to give the databases a unique name.
instance_number
Parameter Type: Integer
Default Value: 0
If Oracle RAC is used, this parameter value is determined based on the number of instances in the RAC.
ldap_directory_sysauth
Parameter Type: String
Default Value: No
When logging in with SYSDBA and SYSOPER, ldap is used to enable / disable directory-based authentication.
Example: LDAP_DIRECTORY_SYSAUTH=no
log_archive_dest_n
Parameter Type: String
Defalut Value: No default value
If FRA is used, database archive log files are stored in this FRA directory by default. With the log_archive_dest_n parameter, we ensure that archive log files are stored in a different location.
Oracle can provide 1 to 31 different locations with 11gR2. This parameter is an important parameter that is also used in the setup of standby databases.
There are some values that this parameter can take as follows. Most of these values are used for the standby database (REOPEN, DELAY, SYNC | ASYNC, AFFIRM | NOAFFIRM, MAX_FAILURE, NET_TIMEOUT, VALID_FOR)
log_archive_dest_state_n
Parameter Type: String
Default Value: Enable
Available Values: enable, defer, alternate
The directory specified by the log_archive_dest_state_n parameter is used to enable / disable usability. The log_archive_dest_n parameter specifies the “enable” value to activate the archive log directory.
If an archive log directory cannot be accessed due to a problem, an alternative archive directory can be specified.
nls_language
Parameter Type: String
Default Value: NLS_LANG is the operating system environment variable
It is used to set the default language of our database.
nls_territory
Parameter Type: String
Default Value: Depends on operating system
Used to specify the default country name for the database.
open_cursors
Parameter Type: Integer
Default Value: 50
Available Values: 0 to 65535
The maximum number of open cursors a session can use
pga_aggregate_target
Parameter Type: Big Integer
Default Type: 10MB or 20% of SGA area
Available Values: Minimum 10 MB, Maximum 4096 GB-1
The PGA field created for each user who connects to the database and logs on is determined by this parameter. If automatic memory management is activated(, we do not need to modify this parameter. Automatically managed by Oracle.
processes
Parameter Type: Integer
Default Type: 100
Available Values: 6 and depends on operating system
Maximum number of operating system users connected to oracle database at the same time.
remote_login_passwordfile
Parameter Type: String
Default Type: exclusive
Available Values: exclusive, shared, none
Checks the Oracle database password file. If we set the value Exclusive (the default value), the password file can only be used by a single database. If we set Shared, one or more database can use password files
sessions
Parameter Type: Integer
Default Type: (1,5 * process) +22
Available Values: 1 to 2^31
It is the parameter that determines the maximum number of sessions that can be created on the system. It must be determined by the maximum number of users connected simultaneously and must always consider running background processes.
sga_target
Parameter Type: Big Integer
Default Type: 0
Available Values: 64 MB and depends on operating system
The SGA_TARGET parameter is the total size of the SGA fields. If this parameter is set to Kilobyte, Megabyte and Gigabyte, the following fields are automatically dimensioned to the given size.
- Buffer cache (DB_CACHE_SIZE)
- Shared pool (SHARED_POOL_SIZE)
- Large pool (LARGE_POOL_SIZE)
- Java pool (JAVA_POOL_SIZE)
- Streams pool (STREAMS_POOL_SIZE)
undo_tablespace
Parameter Type: String
Default Type: First UNDO tablespace name on database
The name of the UNDO tablespace to use when opening the Oracle database instance.
We have looked at the most important parameters and their meaning for the database.
See you next article..
Do you want to learn Oracle Database for Beginners, then read the following articles.
https://ittutorial.org/oracle-database-19c-tutorials-for-beginners/